The United States is warning that it will re-examine its relationship with Ukraine if a presidential election there Sunday fails to meet international standards.
U.S. Deputy Secretary of State Richard Armitage wrote in Friday's Financial Times newspaper that the campaign has already been plagued with violations.
He called on Ukrainian authorities to put an end to the irregularities, which he says include disruption of opposition rallies and stifling of independent news media.
The U.S. mission to the Organization for Security and Cooperation in Europe expressed similar concerns.
U.S. Republican Senator Richard Lugar told the Voice of America in an interview broadcast Friday that the election is very important for Ukraine and those around the world who hope for democracy and human rights.
Prime Minister Viktor Yanukovych and opposition leader Viktor Yushchenko are the top candidates in the hotly contested race.
Some information for this report provided by AP, AFP.